package com.atcumt.alibaba;

import java.util.Scanner;

/* 
 * 3 2 1
 * 110
 * 
 * 3 2 2
 * -1
 */
public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int k = in.nextInt();
        int t = in.nextInt();
        // String s = new String();
        StringBuilder sb = new StringBuilder();
        if (k < t * 2) {
            System.out.println(-1);
        }
        for (int i = 0; i < 2*t; i++) {
            sb.append("1");
        }
        for (int i = 2*t; i < n; i++) {
            if (k - 2*t == 0) {
                sb.append('1');
            } else {
                sb.append('0');
            }
        }
        System.out.println(sb.toString());

        in.close();
    }

}
